In search systems used for frequently asked questions (FAQ) searching or the like, searching has been conventionally done by accepting an input of a search query statement and extracting a word(s) serving as a keyword(s) from the received search query statement. In fuzzy string searching, it has been proposed to do fuzzy string searching by machine-translating, using a database in which text in a first language and its translation in a second language are associated with each other, a query statement in the first language into the second language, and to output text in the first language corresponding to the result of fuzzy string searching. In addition, it has been proposed to translate, in machine translation, an input statement from a first language into a second language, back-translate the translation result, and, based on a distance between the input statement and the back-translation result, calculate the translation reliability.
Examples of the foregoing technologies are discussed in Japanese Laid-open Patent Publication No. 2014-056457 and International Publication Pamphlet No. WO 2013/014877.